Hi,
Welcome!
Profiles and Templates can be confusing. Let's see if I can shed some light....
A Template is both the background and effects used in a listing and it provides structure to the description content including picture placement. You can use one of Auctiva's ready-made templates with lots of wonderful themes, customize one (of theirs) to your own liking, or build your own using their template builder with you own HTML. As good example, you could take one of Auctiva's templates and embed a header for your Store logo. Also, a template only defines structure for code that is embedded in the eBay defined Description section of the listing, i.e. it sets pattern and placement for assembly of that section only.
A Profile is essentially pre-canned content, which is integrated in the listing or can be used as action on a listing. The easiest example to grasp the concept is a Profile for Shipping. If you commonly ship using a flat rate and/or shipping methods, you can create that (just like in the lister) as a pre-built Profile for Shipping. The Profile simply makes it easy to rapid build or change a listing by taking a predetermine set of entries for fill-in for the various sections. You simply select a Profile to integrate on the lister. In that last example, it would be a big time saver to only have to change the code one place, the Shipping Profile, to effect a change to all listings stored using that Profile. A Master Profile is a composite set of the different selected profiles (like assembling a jigsaw puzzle).
You can modify and create Templates at the Listings tab page (lower right).
Profiles are at the Profile tab. Note the add of the new Auto-Relist profile. I mentioned action as well as content. Auto-Relist is a profile to do auto-relist(action) on a listing after close. That one sorta breaks the content mold, but it is a function associated with a listing.
I hope that helps and doesn't confuse.
Danno